/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.activiti.engine.delegate.event;

/**
 * Dispatcher which allows for adding and removing {@link ActivitiEventListener}s to the Activiti Engine as well
 * as dispatching {@link ActivitiEvent} to all the listeners registered.
 * 
 * @author Frederik Heremans
 */
public interface ActivitiEventDispatcher {

	/**
	 * Adds an event-listener which will be notified of ALL events by the dispatcher.
	 * @param listenerToAdd the listener to add
	 */
	void addEventListener(ActivitiEventListener listenerToAdd);
	
	/**
	 * Adds an event-listener which will only be notified when an event of the given types occurs.
	 * @param listenerToAdd the listener to add
	 * @param types types of events the listener should be notified for
	 */
	void addEventListener(ActivitiEventListener listenerToAdd, ActivitiEventType... types);
	
	/**
	 * Removes the given listener from this dispatcher. The listener will no longer be notified,
	 * regardless of the type(s) it was registered for in the first place.
	 * @param listenerToRemove listener to remove
	 */
	 void removeEventListener(ActivitiEventListener listenerToRemove);
	 
	/**
	 * Dispatches the given event to any listeners that are registered.
	 * @param event event to dispatch.
	 */
	 void dispatchEvent(ActivitiEvent event);
	 
	 /**
	  * @param enabled true, if event dispatching should be enabled.
	  */
	 void setEnabled(boolean enabled);
	 
	 /**
	  * @return true, if event dispatcher is enabled.
	  */
	 boolean isEnabled();
}
